In 2004, Omar was arrested and convicted for the rape and torture of Ariel Baskins. Detectives arrested him based on several pieces of evidence: he was last seen harassing Ariel at a bar, was found with her credit cards, his prior offenses, and Ariel identifying him. Detectives Munch and Fin interrogated him first, and when Omar wouldn't crack, Benson took over. Nine hours in the interrogation room, he finally confessed to raping Ariel and Benson closed the case. (SVU: "Quarry")

After he was arrested, Omar immediately recanted his confession but was eventually convicted of rape and sentenced to 300 years at Green Haven Correctional Facility. He began a campaign to try and prove his innocence but he was turned down at every turn for eight years. He used this time to study law and eventually helped other prisoners with their appeals. He repeatedly tried to have the courts reopen his case, but was denied at every turn. When another woman named Gina Logan was raped and tortured the same way Ariel was, Benson immediately suspected Pena had struck again and went to interview him. He continues to profess his innocence and continuously makes rude comments to Benson, to which she retaliates.

The SVU eventually believes that one of Omar's clients, Mike Martinez, raped Gina for him. Benson comes close to another confession when she is stopped by Captain Cragen and Detective Amaro with the fact that he has an alibi. After re-interviewing Ariel, she mentions that the scarf she was gagged with was red. Benson mentions that Omar confessed to using a green scarf. Benson takes out the evidence from 2004, and finds that the scarf is red. Amaro asks her if she was present at the crime scene but Benson says that she was at the hospital with Ariel. She then realizes that the mistake was made by the officer who vouched the evidence. As a result, Omar's confession is revealed to be false.

When Benson talks to Pena about this new information with his new attorney, Bayard Ellis, he flies into a rage, yelling that he told her he was innocent and it took her eight years to realize this. Benson and Ellis try to explain that this is good news but Pena will believe that when he is free. The real rapist, Javier, is arrested after both victims pick him out of a lineup and DNA evidence confirms his responsibility for the attacks. An emergency 440 hearing is held and Omar is finally released, with Omar breaking into tears while the judge gives the order. (SVU: "Justice Denied")